The invention relates to fasteners or anchors and, more particularly, to fasteners or anchors for securement into biological tissue, particularly bone. The invention finds particular application in the securement of sutures to bone, such as the attachment of torn ligaments or ligament replacements to the bone through attachment of the suture to the anchor.
In the medical field, it is frequently necessary to securely attach elements such as ligaments (e.g. rotator cuff ligaments, anterior cruciate ligaments) and prosthetics, to a bone. Such attachment requires, initially, that an anchor be secured within the bone itself. Once the anchor is secured, the ligament or prosthetic can be attached to the anchor through, for example, sutures extending from the anchor.
Various techniques exist for securing an anchor within a bone. In U.S. Pat. No. 6,117,161, assigned to Li Medical Technologies, Inc., for example, a longitudinally extending groove is first made in the bone. An anchor, disposed perpendicularly to an insertion handle, is then inserted into the groove and screwed into the bone until the anchor is held securely therein. Since the anchor is disposed perpendicularly to the handle, it is necessary to prepare a groove large enough to accommodate the size of the anchor including its entire length.
Bones are made of a relatively hard outer layer of tissue made of cortical bone cells and a softer inner layer of tissue made of cancellous cells. By making such grooves in the bone, a larger amount of the harder cortical bone cells must be removed thereby decreasing the affixing strength available for securing the anchor within the bone.
In U.S. Pat. No. 6,102,934, also assigned to Li Medical Technologies, Inc., a rotor blade inserter includes a pushing member having a cam surface thereon that engages with an anchor. The pushing member slides in a channel of a shaft. A collar is disposed on and threaded with a stationary gripping member of a handle. When the handle is rotated and the gripping member is held stationary, the channel of the shaft also rotates, imparting this rotation to the pusher member and thus the collar. The threads of the collar then move with respect to the threads of the stationary gripping member, causing the collar to traverse along the handle, transferring the translational motion to the pushing member, which in turn produces a rotational movement of the anchor about an axis perpendicular to the shaft axis through the engagement of the anchor with the cam surface. In order to insert the anchor into a bone, the surgeon must rotate a handle of the device and also hold the stationary gripping member to allow the collar to traverse the handle. This operation can be cumbersome and difficult to effectuate. An embodiment is disclosed where a spring trigger can be used to apply a force upon the pushing channel when the spring trigger is actuated. However, actuation of the trigger is an additional manipulation which must be performed. In many surgical applications, a surgeon""s hands are occupied by numerous tasks and so it is important to provide a device which can be actuated with as few movements as possible and/or with one hand.
In co-pending U.S. application Ser. No. 09/580,777 filed May 26, 2000, a rotor blade anchor and tool therefor is described. The tool and anchor comprises a handle having a first axis that extends longitudinally with respect to the handle, and a second axis that extends perpendicularly to the first axis, an anchor pivotably coupled to the handle so that the anchor is pivotable about the second axis and a biasing member disposed on the handle, the biasing member biasing the anchor toward a position which is substantially perpendicular to the first axis, the handle being rotatable about the first axis to allow the anchor to rotate about the first axis, the biasing member causing the anchor to penetrate into a bore hole in the biological tissue by pivoting about the second axis, and to screw into the bore hole to attain a position which is substantially perpendicular to the first axis when the anchor is inserted into the bore hole in the biological tissue.
In U.S. Pat. No. 5,203,787 to Noblitt et al., a hole is drilled in a bone and then an anchoring device is inserted into the hole so that a longitudinal axis of the anchoring device is parallel to a longitudinal axis of the hole. A force is then applied to a suture coupled to the anchoring device thereby causing the anchoring device to rotate within the cancellous cells of the bone so that the anchor extends perpendicularly to the longitudinal axis of the hole. The anchor is then held within the bone by abutting against the inside of the harder cortical bone cells. The technique of Noblitt et al., however, requires complex manipulation of the suture to achieve the desired orientation of the anchor.
See also U.S. Pat. No. 5,569,303 to Johnson for an apparatus and method for attaching an object to bone.
Moreover, modern trends in surgery include the restoration of bodily function and form, or repair of anatomical structures through the use of minimally invasive surgical techniques. The ability to surgically repair damaged tissues or joints creating as few and as small incisions as possible, and with ease of manipulation, produces less trauma to the patient, less pain and generally better clinical outcomes.
Thus, there exists a need in the art for a minimally invasive method and device which more securely attaches an anchor within a bone than devices and techniques of the prior art, which does so using a minimum of operator steps and which can be used arthroscopically, employing minimally invasive surgical techniques.
The present invention is an improvement to the above devices in that the anchor is at least partially concealed and spring loaded such that direct axial insertion and arthroscopic use are possible.
It is, therefore, an object of the present invention to provide an apparatus and minimally invasive method for delivering an anchor simply and securely into human tissue.
A further object of the invention is to provide an apparatus and method for emplacing an anchor into a borehole in substantial alignment with the borehole and once inserted, activated so that it engages with the walls of the borehole by moving to a position substantially perpendicular to the borehole.
Such an anchor would be suitable, for example, to repair rotator cuff and other ligament injuries such that the appropriate attachment strength is provided.
It is a further object of the invention to provide such an apparatus which is suitable for arthroscope use in body tissue.
The present invention is directed to an apparatus and a method for delivering an anchor member which sets in biological tissue. The method for delivering the anchor member into biological tissue comprises the following basic steps:
(a) accessing and preparing the intended insertion site;
(b) inserting into the site, through a cannula or otherwise, an anchor member that is set through applying a rotational motion;
(c) after insertion into the site, the anchor member engages the tissue by moving from a first position substantially aligned with a borehole at the site to a substantially perpendicular position (to the insertion angle) through a rotational force. Steps (a) through (c) may be performed through open or minimally invasive surgical techniques, i.e., arthroscopic techniques.
According to a further aspect, the invention comprises a method for securing an anchor to biological tissue, said anchor being detachably and pivotably mounted to an insertion tool, said anchor having a longitudinal axis, said insertion tool having a first axis that extends longitudinally with respect to said insertion tool and a second axis which extends perpendicularly to said first axis, said method comprising the steps of: releasably holding said anchor at a distal end of said insertion tool with said anchor being held at least partly within a sheath member of the insertion tool; inserting said anchor held by said insertion tool, with said longitudinal axis of said anchor being disposed in an orientation that is not perpendicular to said first axis, into a borehole in said biological tissue; actuating a member at a proximal end of said insertion tool thereby to move said anchor distally out of said sheath; applying a biasing force to the anchor to bias said anchor toward a position that is substantially perpendicular to said first axis; said biasing force causing said anchor to rotate about the second axis and engage with a sidewall of said bore hole and to penetrate into said sidewall; rotating said tool about said first axis, whereby said anchor is screwed into said object as said insertion tool is rotated about said first axis and simultaneously rotated about said second axis until said anchor achieves an orientation substantially perpendicular to said first axis; when the anchor is secured in said sidewall, releasing the anchor from said insertion tool, leaving the anchor secured in the biological tissue; and withdrawing the insertion tool.
The above and other objects are also achieved by a tool for securing an anchor to biological tissue, said tool comprising: a handle, a hollow sheath member coupled to the handle having a first axis that extends longitudinally with respect to said handle, and a second axis that extends perpendicularly to said first axis; the distal end of said sheath member being adapted to pivotably and releasably hold an anchor so that said anchor is pivotable about said second axis and being adapted to hold the anchor at least partly surrounded by said sheath member in a first position; a biasing member adapted to bias said anchor about said second axis toward a position which is substantially perpendicular to said first axis; a pusher member adapted to apply a force to said anchor to cause said anchor to move from said first position to a second position distally out of said sheath member; said handle being rotatable about said first axis to allow said anchor, once in said second position out of the sheath member, to rotate about said first axis, said biasing member causing said anchor to penetrate into a bore hole in said biological tissue by pivoting about said second axis, thereby to screw into said bore hole to attain a position which is substantially perpendicular to said first axis when said anchor is inserted into said bore hole in said biological tissue.
These aspects, as well as others, will become apparent upon reading the following disclosure and corresponding drawings.